US2738556A - Air scrabbler system for the air deposition of fibers - Google Patents

Description

M r h 1956 B. E. ANDERSON AIR SCRABBLER SYSTEM FOR THE AIR DEPOSITION OF FIBERS Filed Jan. 13, 1955 United States PatentO AIR SCRABBLER SYSTEM FOR THE AIR DEPOSITION OF FIBERS Bror E. Anderson, Park Ridge, 111., assignor to A. B. Dick Company, Niles, Ill., a'corporation of Illinois Application January 13, 1955, Serial No. 481,632

14 Claims. (Cl. 19-148) This invention .relates to the. air deposition of dry fibers. infthemanufacture. of fibrous structures and it relates more particularly toan improvement in the method and apparatusfor the manufacturev of fibrous structurcs such as described and claimed in the copending applica'tionof Clark et al., Ser. No. 313,316, and entitled Air Scrabbler-System for Fiber Deposition in the Manufacture of Fibrous Structures. In the above-entitled copending application description is made of a fiber depositing system which embodies the principles of a showerhead to cause uniform volumes of fiber and air to pass through the openings of a foraminous separating wall to a collecting wall where the fibers separate out on the surfaces ,thereof to form a fibrous structure. Briefly described, the fiber depositing head comprises a cylindrical housing having a fiber inlet opening in one wall portion and a foraminous separating wall in another portion of the cylindrical housing. The shower-head principle is created by introducing one or more high velocity streams of air tangentially into the housing whereby the fibers become entrained therein and are carried with the air circumferentially about the housing to form a transient layer of air and fibers moving under positive pressure across the faceof the separating wall. The constant movement of the fibers and air across the face of the separatingwall functions eifectively to keep the openings substantially free of entrapped fibers so that fibers and air under positive pressure are able to pass through the openings in substantial constant and uniform volumes to deposit a uniform distribution and concentration of fibers on the surface of the collecting wall.

It is an object of this invention to provide further improvements in apparatus of the type described for the air deposition of dry fibers in the manufacture of fibrous structures.

Another object is to produce apparatus of the type described adapted to impart greater movement to the air and fibers moving about the cylindrical housing and also to provide means for more uniform distribution and 7 separation ofthe fibers entrained withinthe air stream.

It is a related object to provide an improvement in apparatus of the type described adapted to produce improved fibrous structures wherein separated fibers are Figure 3 is a sectional elevational view corresponding 2 to that of Figures 1 and 2 embodying a further modification in a fiberdepositing head; and

Figure 4 is a sectional elevational view taken substantially along the line 4-4 of Figure 3.

As shown in Figure 1 of the drawing, a fiber depositing head embodying features of this invention comprises an outer cylindrical housing 10 having a feed chute 11 in communication with a feed opening 12 in the upper wall portion for introducing separated fibers into the cylindrical housing. The feed opening12 may extend over only a portion of the housing but it is preferred to have the feed opening extend substantially across the housing so as to be able to introduce fibers in substantially uniform distribution across the entire widthof the housing.

The underside of the housing is provided with a separating wall portion13 preferably in the form of a separatedplate secured to the underside of the housing or else formed as an integral part thereof. The foramens in the separating wall may comprise elongate slots extending transversely across the housing in circumferentially spaced apart relation or they may be in the form of separate openings such as exist in screen members, or in plates of the type described in the copending application of James dA. Clark, Ser. No. 61,674, filed November 23, 1948.

One or more air nozzles 14 are positioned to extend withirrthe housing to direct one or more high velocity streams. of air in a tangential direction to impart circulating movement of the air about the housing. These air nozzles may be positioned in separate inlets arranged laterally across the"housing to introduce a plurality of tangential-streams of air directed at corresponding or at varying angles but preferably in a direction less than J radial and in a direction other than to direct the air stream onto the surface of the separating wall thereby to avoid interference with the movement of air and fibers as aitransient layer across the face of the separating wall. Instead, the air nozzles may be adapted to introduce the air stream as a substantially continuous blade extending across the housing-such as is described in the aforemen-. tioned copending application of Clark et al., of which collectingwall may be a stationary member or it may be in the form of an endless belt moving in one direction. and adapted continuously to separate fibers on the, surface thereof' to form an interfeltcd fibrous web. In any event itis desirable to locate the collecting wall in the fiber depositing zone over a suction device whereby .air is withdrawn through the collecting wall, tohold the deposited fibers on the surfaces thereof. In the event that theamount'of air withdrawn through the collecting wall is greater than that which passes through the separating wall,- the deficiency is made up by a slight inflow of air from the surrounding atmosphere into the space between the separating wall and the collecting wall thereby to, permit the area to remain open to the atmosphere without interference with the movement of fibers and without dispersion of fibers out into the atmosphere as has been characteristic of fiber depositing systems heretofore emof the type describedand claimed in said copendingap-m plication for .causing air and fibers to move as a constant layer under. positive pressure over the face of. the separating wall to generate a type of shower-head principle where,

by air and fibers in substantially uniform volumes and Patented Mar. 20, 1956 concentration pass through the openings .of the separating Wall 13 to the collecting wall 15.

It has been found that considerable improvement in the transmission of fibers in-uniform distributionand concentration through the separating =wall results fromthe modi fication 'whereby' the circulating movement of air and fibers about the housing is. confined within a'limited annular space adjacent the outer wall of the cylindrical housing Thelinearmovementof air and-fibers is markedly increaseduthereby to secure :better fiber=distribution while at .thezsame time improving thecharacteristics operating to :maintaintheshower-head principle forcausing more uniforrnvolumes of fibertand .air to pass through the openings. inthe separating wall.

In; accordance with the practice of this invention; characteristics ;of.the..:type described forchanneling the fiber entrained air. streams isiachievedbythe use of a shell 16 of-elliptical. or cylindrical shape positioned within the housingto provide. an annularspace therebetween.

As..illustrated in Figure l, it .is preferred to make use of .an..elliptical shell. :positioned. to providea decreasing spaced relation with the housing .walls in the area adjacent the separating wall and anincreasing spaced relation in-the area therebeyond with maximum space adjacent the feed opening thereby to increase the turbulence and velocityof the air stream as itpasses .over the separating walland materially to decrease the velocity of the air as it approaches and passes the feed opening thereby to provide for less interference withthefeeding relation-and less: tendency for thefibers tobe thrown outwardly by centrifugal force to form interfeltedrbundles which interfere withthe uniform transmission .of separated fibersv through the. separating walla In.Figures 2 and 3, illustra-' tion is. made of the use of a cylindricalshell substantially concentrically mounted within the housing to definean annular space for circulation of the fiberientrained air stream;

With this modification in the constructiomthe. air inlet nozzles '14 maybe. positioned to extend substantially tangentially into the annular space between the housing and shell either through the housing, asqdescribedtand illustrated in Figures 1 and 2, orthroughtheshellv member as .shown'in Figure 3. When positioned in..thev outer: cylindrical housing, it is best if the angular relationship of the introduced air stream is adjusted to direct the stream so as not abruptly to impinge upon the adjacent shell wall, otherwise the desired circulatingmovements will not result. It is preferredto avoiddirecting-the.air. stream atany-portion of the shell .andto .avoid .direeting thesair. streamso as to impinge on .the separating :wall. portion where it might interfere with movement of .air and fibers" thereover.

When located to extend through the-shell wall, it.is only: necessary to avoidv directingthe-air stream-ontoihe sepa-. rating wall and to maintain .anangularrelation asnearly; tangential as possible .to achieve the. desired aturbulence coupledwith circulating movement.

Various combinations .of nozzles mounted on -.the cylin-.

drical housing or shell wall may 'be arranged to give the desired air scrabbler action embodying the .described shower-head principle.

As. shownin Figure 1, separated fibers are fed down-. wardly. through the feed hopper 11, through the'feed open-. ing 12 into the interior. ofv the cylindrical housinglfl. One or more air streams. athigh velocity are introduced.tangentially into the housing by air nozzles 14 located just beyond the fiber feed opening .12..

The air nozzles are positioned to direct: the air. stream tangentially into the housing to passjust belowthe hell butbeyond-the farthest endof the. separating wall pertion-13 located in the underside of. .the.'housing,,.

As 'a'result .of the introduction .of .'such;.high,.velocity air streams tangentiallyinto the housing theair. streams. arecausedconjointly but in somewhat: turbulent. move-. ment'to circulate about the housing within the space defined between the shell. and the inner wall of the housing; The fibers become uniformly entrained therein and are carried with the air stream about the housing so that the air and fibers move as a transient fluid layer over the inner face of the separating wall 13. As a result, the openings in the separating wall are "kept substantially free of fibers and uniform volumes of fibers and air pass through the separating Wall 13 to the collecting wall'15.

Air is withdrawn by exhaust means in communication with ductwork 17 from the underside of the.collecting wall 15 in the fiber depositing zone to create a suction which anchors the deposited fibers onto the surface thereof.

By way of still further modification to achieve better fiber separation and distribution in the circulating air stream, breaker plates in the form of paddle members 18 are mounted to operate within the confinedannular space 21 through which the air and fibers circulate. Thebreaker plates may be in the form of a rigid .bar dimensioned to have a width substantially corresponding to the distance between the walls of the housing and'the shell anda length corresponding to that of the housingso as substantially fully to occupy the space therebetween'when positioned to extend radially between the shell and housing.

The plate is adapted to be secured onto a shaft 19 rotatathrough.

Rotational movement of the breaker plate or paddle wheel 18 in the clockwise direction in Figure '2 causes displacement of the fibers thrown toward the outerwvall' of the housing by centrifugal force -to the inner portion" ofthespace so as to effect better distribution; The plate also operates to minimize the agglomeration of fibers or' the bunching of fibers during movement through the confining space and it further functions to impact the fibers and break up the fiber bundles or masses in a manner to secure separation and better fiber distribution.

Instead of a singlepaddlewheel of the typevdescribed, two or more aligned paddle wheels or platemembers'may be rotatively mounted on separate shafts for simultaneous rotational movement Within the area between the housing For example, in Figures 3 and '4, there is illus-- and shell. trated an assembly formed with two paddle wheels 30 and 3lzradially aligned and dimensioned to occupy the space between the;shell. and the housing. The plates maybedimensioned to correspond to one-half the distance -be-- tween said cylindrical elements in the'event. that a meeting relation exists but, if the 'plates are 'adaptedto'bc spacedso that one doesnot interfere with. the rotational movement of. the other, the plate members-maybe of Separate shafts 32 and '33.operatively larger dimension. connected to the breaker plates are provided with spindles 34and 35 connected to driving means for rotational movement of the plates in the .same or .in opposite directions but with. the .outer plate. preferably located in :the clock wise direction to effect displacement. of the fibers-fromthe outer portions to which they are vgenerally-thrown by gravitational force.

The breaker plates or rotatable paddle wheels may be= located in any portion .of the. housing otherzthan between' the air inlet nozzles and the separating wallzand 'more than one breaker plate section may betused'where desirable It will i to achieve better fiber separation and distribution. beevident also that the breaker plates functiontointerrupt the linear fiow of air and fibers and causerturbulent fiow of a character which minimizes fiber agglomeration."

While description has been given of a particular construc=- tion:for the breaker plates, it.will..be.apparent that-ihe concepts of the invention embody the use of other comventional disintegrating or separating apparatus capable of separating and/ or displacing the fibers to achieve better fiber distribution as they circulate about the housing.

Othermodifications, such as the use of a plurality of air inlets mounted both in the outer housing and in the shell wall or in one or the other may be used with or without radially extending air inlets to impart turbulence in addition to the breaker plates or separate therefrom in the absence of-such breaker plates.

As used in the specification and in the claims, the term cylindrical as it refers to the shell and also to the housing is intended to include shells and housings of various shapes but of curvilinear contour such as ellipsoidal, oblate, and the like.

It will be understood that various changes may be made in the details of construction, arrangement and operation without departing from the spirit of the invention, especially as defined in the following claims.

I claim:

1. In apparatus for the air deposition of dry fibers to form a fibrous structure, a cylindrical housing having an inlet in one wall portion and a separating wall defining a wall portion spaced from the inlet and having openings dimensioned to permit passage of fibers, a shell substantially arranged within the housing to define an annular space therebetween, air nozzles extending into said annular space for directing high velocity streams of air in a tangential direction therein, and means for feeding fibers through the inlet into the space where the fibers become entrained in the air stream and are carried with the air as a moving layer across the face of the separating wall for passage therethrough in substantially uniform concentrations.

2. In apparatus for the air deposition of dry fibers to form a fibrous structure, a cylindrical housing having an inlet in one wall portion and a separating wall defining another wall portion having openings dimensioned to permit passage of fibers, a cylindrical shell arranged within the housing and ofiset in the direction of the separating wall to provide a smaller spaced relation therebetween and increasing spaced relation toward the inlet in the housing, air nozzles extending into the annular space for directing high velocity streams of air tangentially therein, and means for feeding fibers through the inlet into the annular space where the fibers become entrained in the air stream and are carried with the air as a transient layer across the face of the separating wall for passage therethrough in substantially uniform concentrations.

3. Apparatus as claimed in claim 1 in which the shell comprises an ellipsoidal member.

4. Apparatus as claimed in claim 1 in which the shell comprises an ellipsoidal member positioned to define a space of decreasing dimension between the shell wall and the separating wall portion of the housing.

5. Apparatus of the type claimed in claim 1 in which the air nozzles extend through the cylindrical housing into the annular space.

6. Apparatus of the type claimed in claim 1 in which the air nozzles are positioned in the cylindrical shell to direct the air streams tangentially into the annular space.

7. Apparatus of the type claimed in claim 1 in which the air nozzles are located both in the cylindrical housing and in the cylindrical shell for directing air streams tangentially into the annular space therebetween.

8. Apparatus for the air deposition of dry fibers to form a fibrous structure comprising a cylindrical housing having an inlet in one wall portion and a separating wall defining another having openings dimensioned to permit passage of fibers, a collecting wall spaced a short distance from the separating wall and having openings dimensioned to prevent passage of fibers, a cylindrical shell arranged within the housing to define an annular space therebetween, inlet means for directing high velocity streams of air tangentially into the space between the shell and housing, and means for feeding fibers through the inlet into the annular space where the fibers become entrained in the air stream and are carried with the air about the annular space to pass as a moving layer across the face of the separating wall whereby fibers are carried with the air through the openings of the separating wall for separation onto the collecting wall. 7

9. Apparatus as claimed in claim 8 in which the collecting wall comprises an endless member moving in one direction to form a fibrous web thereon.

10. Apparatus as claimed in claim 8 which includes means for withdrawing larger volumes of air from the underside of the collecting wall than is able to pass through the separating wall whereby the deficiency is made up by a slight inflow of air from the surrounding atmosphere into the space between the separating wall and the collecting wall.

11. Apparatus for the air deposition of dry fibers to form a fibrous structure comprising a cylindrical housing having an inlet in one wall portion and a separating wall defining another having openings dimensioned to permit passage of fibers, a collecting wall spaced a short distance from the separating wall having openings dimensioned to prevent passage of fibers, a cylindrical shell positioned within the housing to define an annular space therebetween, air inlet means for directing high velocity streams of air tangentially into the cylindrical space, a paddle wheel assembly positioned within the annular space for rotational movement about an axis parallel to that of the housing, and means for feeding fibers through the inlet into the cylindrical space whereby the fibers become entrained in the air stream and are carried therewith about the cylindrical space for passage as a moving layer across a face of the separating wall whereby substantially uniform volumes of air and fiber pass through the openings thereof.

12. Apparatus for the air deposition of dry fibers to form a fibrous structure comprising a cylindrical housing having an inlet in one wall portion and a separating wall defining another having openings dimensioned to permit passage of fibers, a collecting wall spaced a short distance from the separating wall having openings dimensioned to prevent passage of fibers, a cylindrical shell positioned within the housing to define an annular space therebetween, inlet means for introducing high velocity streams of air tangentially into the cylindrical space, means for feeding fibers through the inlet into the cylindrical space whereby the fibers become entrained and are carried with the air stream about the cylindrical space for passage as a moving layer over the face of the separating wall whereby substantially uniform volumes of air and fibers are carried through the separating wall to the collecting wall, a paddle wheel assembly mounted in the annular space for rotational movement about an axis parallel to the axis of the housing and dimensioned lengthwise substantially to correspond to the length of the cylindrical space and dimensioned in width to correspond to the distance between the shell and housing, and means for rotating the paddle wheel assembly for effecting more uniform distribution and separation of fibers carried with the air about the cylindrical space.

13. Apparatus for the air deposition of dry fibers to form a fibrous structure comprising a cylindrical housing having an inlet in one wall portion and a separating wall defining another having openings dimensioned to permit passage of fibers, a collecting wall spaced a short distance from the separating wall having openings dimensioned to prevent passage of fibers, a cylindrical shell substantially concentrically positioned within the housing to define a cylindrical space therebetween, inlet means for introducing high velocity streams of air tangentially into the cylindrical space, means for feeding fibers through the inlet into the cylindrical space whereby the fibers become entrained and are carried with the air stream about the cylindrical space for passage as a moving layer over the face of the separating wall whereby substantially uniform volumes of air and fiber are carried through :the separating wall to the collecting ,wall; a paddle'wheel assembly positioned-twithin the cylindrical space for rotational move-' ment about. an-axis parallel totthe housing, and driving means for rotatingthe paddle wheels in a direction to displace the fibers from an area adjacent the housing wall to an area adjacent the shellwall during rotation of the fibers with the air stream'aboutt the cylindrical space.

14. Apparatus asclaimedin claim 12 in which the paddle Wheel assembly comprises a pair of breaker plates mounted for rotational. movement about separate radially aligned .axes-parallelto the axis of the housingand:dimenesioned .to have a Width corresponding to one-halfthe dis-' tance between the walls of the housing and :shell,$and means for rotating the plates in opposite direetions'rwith the-outer plate turning in a direction to displace the fibers inwardly from the'portion adjacent thehousing wall..

Clark et al. Nov. 22,..1949-

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